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  • Brightness control in a uLCD

    Hello,

    I have a uLCD-28PT, and I have tested in SGC (R19) and in GFX (R25) mode, but I can't control the brightness of the LCD, only the backlight control to ON and OFF.

    I have seen several posts with this thread, and in some of then you say that "4D Systems has acknowledged that this is a feature they intend to implement in a future release of PmmC code for the uLCD products". When can be implemented that feature?

    In my application, the LCD seems to be very darkness during the day. With less sun, the display looks well.

    In the post http://4d.websitetoolbox.com/post?id=4788422, appears a possible solution, but I do not get it to work on my display.

    Help... Thanks.

  • #2


    Most LCD displays do not have the ability to adjust the backlight.

    The one you are referring to is a special driver chip that has PWM builtin to enable dimming the display. Note I said dimming, at full brightness it will still exhibit the same problems you are seeing.

    Regardless, LCD displays, unless specifically designed to work in sunlight nearly always look very dark, or invisible. Cranking up the backlight is a very partial solution but there's more to it than that.

    This is why a lot of people use OLEDs, they fair a lot better in sunlight, they are still not 'perfect' though. Unfortunately 2.8" oleds are not available in reasonable quantities at this time
    Mark

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    • #3


      Thanks for your fast reply.

      I think I should have bought a uOLED-32028-P1T...

      But now, you say that "cranking up the backlight isa very partial solution", this means that's possible to change de backlight leds?

      Also, how can I use the special driver chip that has PWM builtin?

      Thanks.

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      • #4


        Read here http://en.wikipedia.org/wiki/Transflective_liquid_crystal_display

        You need a different sort of LCD for what you are trying to do.
        Mark

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        • #5


          None of the current display modules have the ability to control LED back light brightness.

          Usually, reducing the back light intensity is done to reduce power for battery applications and this would be a good feature to have for lower power modes.

          As with all LCD displays, Increasing the back light intensity will not improve the display brightness in sunlight, if anything it will just make it more washed out.

          Usually for direct sunlight applications, reflective LCD technology is used.

          Even with OLED displays, they are no good for direct sunlight applications,
          but usually look a lot better than LCD's in moderate daylight conditions.
          Regards,
          Dave

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